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ppmdist - simplistic grayscale assignment for machine generated, color
images
ppmdist [-intensity|-frequency] [ppmfile]
Reads
a portable pixmap as input, performs a simplistic grayscale assignment
intended for use with grayscale or bitmap printers.
Often conversion from
ppm to pgm will yield an image with contrast too low for good printer output.
The program maximizes contrast between the gray levels output.
A ppm input
of n colors is read, and a pgm of n gray levels is written. The gray levels
take on the values 0..n-1, while maxval takes on n-1.
The mapping from color
to stepped grayscale can be performed in order of input pixel intensity,
or input pixel frequency (number of repetitions).
- -frequency
- Sort
input colors by the number of times a color appears in the input, before
mapping to evenly distributed graylevels of output. -intensity Sort input
colors by their grayscale intensity, before mapping to evenly distributed
graylevels of output. This is the default.
Helpful only for images with
a very small number of colors. Perhaps should have been an option to ppmtopgm(1)
.
ppmtopgm(1)
, ppmhist(1)
, ppm(5)
Copyright (C) 1993 by Dan
Stromberg.
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